Remote-plasma clean (rpc) directional-flow device

ABSTRACT

Various embodiments include apparatuses, systems, and methods for using a remote-plasma cleaning system with a directional-flow device for concurrently cleaning multiple processing stations in a processing tool used in the semiconductor and allied fields. In one example, an apparatus used to perform a remote-plasma clean (RPC) in a multi-station process chamber is disclosed and includes an RPC directional-flow device that is to be coupled between an RPC reactor and the process chamber. The RPC directional-flow device includes a number of ramped gas-diversion areas to direct at least a radical species generated by the RPC reactor to a separate one of the processing stations. An incoming cleaning-gas diversion hub is to receive the radical species and distribute at least the species substantially-uniformly to each of the of the ramped gas-diversion areas. Other apparatuses, systems, and methods are disclosed.

INCORPORATION BY REFERENCE

An Application Data Sheet is filed concurrently with this specificationas part of the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed Application Data Sheet is incorporated by referenceherein in its entirety and for all purposes.

TECHNOLOGY FIELD

The disclosed subject matter is generally related to the field ofcleaning processing chambers used in the semiconductor and alliedfields. More specifically, the disclosed subject matter is related tousing a remote-plasma cleaning system with a directional-flow device.

BACKGROUND

As is known in the art, various deposition processes are used to depositfilms in forming integrated circuits and related devices by variousmethods including plasma-enhanced chemical vapor deposition (PECVD) andatomic-layer deposition (ALD). However, a consequence of the depositionprocess is that the various materials (e.g., film depositions) are notonly deposited onto a substrate undergoing a process, but also on theinterior surfaces of the process chambers in which the depositionsoccur. Consequently, films from the deposited materials are formed onthe interior surfaces of the process chambers. The films continue toaccumulate over time. Additionally, the films can dissolve, detach, orotherwise disperse through the process chamber causing contamination.Therefore, the accumulated films are periodically removed, by variousprocesses known in the art, from the process chambers to avoid suchcontamination.

For example, FIG. 1A shows a plasma direct-cleaning system 100 of theprior art used to clean interior portions of a single process-chamber101. FIG. 1A shows a gas-inlet port 117, connected to a gas-distributionshowerhead 103. Below the gas-distribution showerhead 103 is a substratepedestal 105 designed to hold a substrate (e.g., a wafer comprising anelemental semiconductor, such as silicon, a wafer comprising a compoundsemiconductor, or other substrate types known in the art) undergoing afilm deposition process. The substrate pedestal 105 is pneumatically andmechanically coupled to a gate valve 107, which can be opened to exhaust119 process gases to a pump (not shown). Various interior surfaces ofthe single process-chamber 101 are coated with films 111A.

During a direct-cleaning process, cleaning gases (e.g.,fluorine-containing compounds such as hexafluoroethane (C₂F₆, also knownas carbon hexafluoride) or octafluoropropane (C₃F₈, also known asperfluoropropane), which are often mixed with oxygen (O₂) as plasmaetching-materials, are injected into the gas-inlet port 117. Aradio-frequency (RF) generator 109 is used to produce a plasma 113within the single process-chamber 101. Fluorine atoms are readilydissociated from the fluorine-containing compounds within the plasma113. As is known in the art, fluorine atoms are highly electronegativeand are highly reactive with many types of materials, typically forminga volatile by-product that is pumped out of the processing chamber 101that can be removed by the pump through the exhaust 119.

FIG. 1B shows results 130 of a high-pressure clean on the interiorportions of the single process-chamber 101 using the plasmadirect-cleaning system 100 in accordance with FIG. 1A. Although many ofthe films have been reduced to thinner or non-continuous films 111B,most of the films 111A still remain. Consequently, the results 130indicate that the process chamber 101 is incompletely cleaned.

FIG. 1C shows results 150 of a low-pressure clean on the interiorportions of the single process-chamber 101 using the plasmadirect-cleaning system 100 in accordance with FIG. 1A. Although most ofthe films 111A remaining from the high-pressure clean have been removed,thinner or non-continuous films 111B still remain. Thus, the processchamber 101 is still incompletely cleaned.

Moreover, the plasma direct-cleaning system 100 has additionaldisadvantages in that plasma-generated ions continuously bombard theinterior surfaces of the processing chamber 101 and can cause damage toassociated hardware with the ions. Additionally, as shown, the plasmadirect-cleaning system 100 may not completely clean peripheral areaswithin the single process-chamber 101, or areas that are difficult toaccess such as around robotic parts such as lift pins (not shown), orwithin the gas-distribution showerhead 103. Further, the plasmadirect-cleaning system 100 can be more difficult to implementsuccessfully and efficiently within multi-chamber or multi-stationprocessing tools that are becoming increasingly common insemiconductor-fabrication environments.

The information described in this section is provided to offer theskilled artisan a context for the following disclosed subject matter andshould not be considered as admitted prior art.

SUMMARY

In various embodiments, the disclosed subject matter describes a anapparatus to direct radical species. The apparatus comprises aremote-plasma clean (RPC) directional-flow device that is configured tobe coupled between an RPC reactor and a multi-station process chamber.The RPC directional-flow device includes multiple, ramped gas-diversionareas. Respective ones of the multiple, ramped gas-diversion areas areconfigured to direct at least the radical species generated by the RPCreactor to a separate one of multiple processing stations within themulti-station process chamber. A number of the ramped gas-diversionareas is at least equal to a number of the multiple processing stations.An incoming cleaning-gas diversion hub is arranged to receive at leastthe radical species from the RPC reactor and distribute at least theradical species substantially-uniformly to each of the multiple, rampedgas-diversion areas.

In various embodiments, the disclosed subject matter describes adirectional-flow device to distribute an incoming-gas flow. Thedirectional-flow device includes multiple, ramped gas-diversion areas.Respective ones of the multiple, ramped gas-diversion areas are arrangedto direct the incoming-gas flow to a separate one of multiple processingstations within a multi-station process chamber. A number of the rampedgas-diversion areas is at least equal to a number of the multipleprocessing stations. An incoming-gas diversion hub is arranged toreceive and split the incoming-gas flow substantially-uniformly anddistribute the incoming-gas flow to at least each of the multiple rampedgas-diversion areas.

In various embodiments, the disclosed subject matter includes aremote-plasma clean (RPC) directional-flow device. The RPCdirectional-flow device includes multiple, ramped gas-diversion areas.Respective ones of the multiple, ramped gas-diversion areas areconfigured to direct at least a radical species generated by an RPCreactor to a separate one of multiple processing stations within amulti-station process chamber. A multi-ribbed wall separates each of theramped gas-diversion areas. The multi-ribbed wall has a channel locatedbetween each multi-ribbed wall separating the ramped gas-diversionareas. An incoming cleaning-gas diversion hub is arranged to receive atleast the radical species from the RPC reactor and distribute at leastthe radical species substantially-uniformly to each of the multiple,ramped gas-diversion areas.

BRIEF DESCRIPTION OF FIGURES

FIG. 1A shows a plasma direct-cleaning system of the prior art used toclean interior portions of a single process-chamber;

FIG. 1B shows results of a high-pressure clean on the interior portionsof the single process-chamber using the plasma direct-cleaning system inaccordance with FIG. 1A;

FIG. 1C shows results of a low-pressure clean on the interior portionsof the single process-chamber using the plasma direct-cleaning system inaccordance with FIG. 1A;

FIG. 2A shows a remote-plasma clean (RPC) system of the prior art usedto clean interior portions of a single process-chamber;

FIG. 2B shows results on the interior portions of the singleprocess-chamber using the of the RPC system in accordance with FIG. 2A;

FIG. 3 shows a multi-station substrate-processing tool of the prior art;

FIG. 4A shows a computational fluid dynamic (CFD)-based simulationshowing a vector field of an RPC inlet flow of the prior art whenapplied to one station of the multi-station substrate-processing tool ofFIG. 3;

FIG. 4B shows a CFD-based simulation showing flow streams of an RPCinlet flow of the prior art when applied to one station of themulti-station of FIG. 3;

FIG. 5 shows a cross-section of one station of a multi-stationsubstrate-processing tool using an RPC directional-flow device inaccordance with an embodiment of the disclosed subject matter;

FIGS. 6A through 6C show various exemplary embodiments of an RPCdirectional-flow device in accordance the disclosed subject matter;

FIGS. 7A and 7B various exemplary embodiments of a multi-walled RPCdirectional-flow device in accordance the disclosed subject matter;

FIGS. 8A and 8B show exemplary physical dimensions for the multi-walledRPC directional-flow devices of FIGS. 7A and 7B;

FIG. 9A shows a CFD-based simulation showing a vector field of an RPCinlet flow using an RPC directional-flow device in accordance thedisclosed subject matter when applied to one station of a multi-stationsubstrate-processing tool; and

FIG. 9B shows a CFD-based simulation showing flow streams of an RPCinlet flow using an RPC directional-flow device in accordance thedisclosed subject matter when applied to one station of a multi-stationsubstrate-processing tool.

DETAILED DESCRIPTION

The description that follows includes illustrative examples, devices,and apparatuses that embody various aspects of the disclosed subjectmatter. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide anunderstanding of various embodiments of the inventive subject matter. Itwill be evident however, to those of ordinary skill in the art, thatvarious embodiments of the disclosed subject matter may be practicedwithout these specific details. Further, well-known structures,materials, and techniques have not been shown in detail, so as not toobscure the various illustrated embodiments.

Various exemplary embodiments discussed herein below focus on providingmore efficient cleaning of process chambers by directing a clean gasflow (or more generally, an incoming-gas flow) to each pedestal andshowerhead station within a multi-station processing tool. Embodimentsof the disclosed subject matter also reduce or minimize recombination ofvarious types of cleaning compounds (e.g., oxygen (O₂) in whichrecombination is much more aggressive than, for example, nitrogentrifluoride (NF₃). Various embodiments may also serve to reduce orminimize heating of the spindle and indexer assembly.

Although certain types of remote-plasma cleaning (RPC) systems forinteriors of process chambers have been considered in the past, thefeasibility of using these RPC systems in certain situations is limited.For example, as described below, multi-chamber or multi-station systemscannot effectively use the standard RPC systems of the prior art.Nonetheless, a person of ordinary skill in the art will recognize thesignificant importance of various embodiments of the disclosed subjectmatter upon a brief review of contemporaneous RPC cleaning systems.

For example, FIG. 2A shows a remote-plasma clean (RPC) system 200 of theprior art used to clean interior portions of the single process-chamber101. The RPC system 200 is also shown to include an RPC reactor 205 intowhich a plasma 201, along with source gases 203, may be combined. Thesource gases (e.g., cleaning gases) may include, for example, nitrogentrifluoride (NF₃), carbon tetrafluoride (CF₄, also known astetrafluoromethane), carbon hexafluoride (C₂F₆, also known ashexafluoroethane), octafluoropropane (C₃F₈, also known asperfluoropropane), and other fluorine-containing compounds, along withArgon (Ar) and/or oxygen (O₂).

As is known in the art, one or more radical species may be generated inthe RPC reactor 205 and configured to enter the single process-chamber101 via a gas inlet 207 couple to the single process-chamber 101 fromthe RPC reactor 205. Any type of plasma source may be used in the RPCreactor 205 to create the radical species. This includes, but is notlimited to, capacitively coupled plasmas, microwave plasmas, DC plasmas,and laser-created plasmas. An example of a capacitively coupled plasmacan be a radio frequency (RF)-generated plasma. A high-frequency plasmacan be configured to operate at 13.56 MHz or higher. An example of suchthe RPC reactor 205 can comprise various products within the GAMMA®family (manufactured by Lam Research®, 4650 Cushing Parkway, Fremont,Calif. 94538, USA). Another example of the RPC reactor 205 known in theart is the ASTRON® ex reactive gas generator (manufactured by MKSInstruments, Inc., 2 Tech Drive, Andover, Mass. 01810, USA), which canbe operated at 440 kHz. Additionally, a microwave plasma generator canbe used as the RPC reactor 205, such as the ASTeX® (also manufactured byMKS Instruments, Inc.). A microwave plasma can be configured to operateat a frequency of 2.45 GHz. As explained below in greater detail,various embodiments of the disclosed subject matter may be usedregardless of the type of reactor chosen. Various types of the RPCreactor 205 may be provided as a subunit mechanically coupled onto alarger apparatus used for processing one or more substrates in parallel.

FIG. 2B shows results 230 on the interior portions of the singleprocess-chamber using the of the RPC system 200 in accordance with FIG.2A. The results indicate that each of the gas-distribution showerhead103 and the pedestal 105 are free, or generally free, of any depositedmaterials (e.g., films). Therefore, the RPC process provides asubstantially complete cleaning of interior portions of the singleprocess-chamber 101. However, each of these prior art devices, asdiscussed in more detail below, is manufactured for use with only asingle processing chamber. There is presently no effective way todeliver the radical species into multiple processing stationsconcurrently.

For example, FIG. 3 shows a multi-station substrate-processing tool 300of the prior art. However, although the multi-stationsubstrate-processing tool 300 is known, similar or the same types ofsubstrate-processing tool may be used with various embodiments of thedisclosed subject matter as well.

The multi-station substrate-processing tool 300 includes a plurality ofprocess stations 301A, 301B, 301C, 301D in a processing chamber 303.Although four stations are shown, a person of ordinary skill in the artwill recognize that a larger or smaller number of stations may be used,along with appropriate changes. As is known to a skilled artisan, bymaintaining each station in, for example, a low-pressure environment,defects caused by vacuum breaks between film-deposition processes may bereduced or avoided.

As is further shown in FIG. 3, the multi-station substrate-processingtool 300 includes a substrate inbound-load-lock 305 and a substrateoutbound-load-lock 307, either or both of which may include aremote-plasma source (not shown but understandable to a person ofordinary skill in the art). A robot 317, generally at atmosphericpressure, is configured to move substrates from, for example, a cassetteloaded through a substrate carrier 319 (e.g., such as a front-openingunified pod (FOUP) or other type of standard mechanical interface(SMIF)) into substrate inbound-load-lock 305 via an atmospheric port315. A substrate is selected and placed by the robot 317 on a pedestal309 in the substrate inbound-load-lock 305. The atmospheric port 315 isclosed, and the load lock is pumped down to less than atmosphericpressure (e.g., a few Torr or less).

Where the substrate inbound-load-lock 305 includes a remote plasmasource, the substrate may be exposed to a remote-plasma treatment in theload lock prior to being introduced into the processing chamber 303.Further, the substrate also may be heated in the substrateinbound-load-lock 305 to, for example, remove moisture and adsorbedgases. Next, a chamber transport port 311 to the processing chamber 303is opened, and another robot (not shown) places the substrate into theprocessing chamber 303 on a pedestal 313 at the process station 301A.While the embodiment depicted in FIG. 3 includes load locks, it will beappreciated that, in some embodiments, direct entry of a wafer substrateinto the processing chamber 303 may be provided.

As noted above, the processing chamber 303 shown in FIG. 3 provides fourprocess stations, 301A, 301B, 301C, 301D. Process gases may be providedby a single, process-gas inlet 321. Further, each process station mayhave a heated pedestal (for example, the pedestal 313 for the processstation 301A) and various gas line inlets (note shown). Themulti-station substrate-processing tool 300 can also include asubstrate-handling system for transferring substrates within theprocessing chamber 303 (e.g., from one of the process stations toanother). Such types of substrate handling systems and related roboticmechanisms are known in the art. However, as noted above, there ispresently no effective way to deliver the radical species into multipleprocessing stations concurrently.

FIG. 4A shows a computational fluid dynamic (CFD)-based simulation 400showing a vector field of an RPC inlet flow of the prior art whenapplied to one station of the multi-station substrate-processing tool300 of FIG. 3. As is known to a person of ordinary skill in the artconversant with CFD analysis, only a single process station is shown asresults in remaining ones of the process stations (not shown) would besubstantially identical in this situation as results would be mirroredalong two axes (e.g., on the back edge and the left edge of the processstation 301A).

A person of ordinary skill in the art will immediately recognize thatthe vectors are indicative of an extremely non-uniform velocity filed ofthe incoming RPC gases. For example, the vectors indicate a relativevelocity of gases within the process station 301A of the processingchamber 303. At the single, process-gas inlet 321, the vectors arerelatively large, indicating a high velocity of incoming gases includingthe radical species generated within, for example, the RPC reactor 205of FIG. 2A. As the incoming gases containing the radical species movefarther from the process-gas inlet 321 toward a facilities exhaust port401, the vectors within the vector field are much smaller, thusindicating a lower velocity of the incoming gases. Due to the reducedvelocity of the gases, there is also a concomitant reduction in efficacyof the radical species for cleaning.

FIG. 4B shows a CFD-based simulation 430 showing flow streams of an RPCinlet flow of the prior art when applied to one station of themulti-station of FIG. 3. A person of ordinary skill in the art willrecognize that the flow streams, much like the vector fields of FIG. 4A,are indicative of a lower-velocity of the incoming gases along with areduction of the flow streams as the gases continue farther from theprocess-gas inlet 321.

The foregoing examples are provided merely as examples to offer theskilled artisan a context for the following disclosed subject matter andshould not be considered as admitted prior art.

As an overview, various embodiments of the disclosed subject matterdirect RPC gases, coming from an RPC gas-inlet, past a directional-flowdevice to between a gas-distribution showerhead and a substrate pedestalarea within each process station. Although the following embodimentsdepict directional-flow devices used with four process stations, theactual number of process stations served by the various embodiments ofthe directional-flow device may be increased or decreased as needed fora given processing tool. For example, upon reading and understanding thedisclosed subject matter, a person of ordinary skill in the art willrecognize that the directional-flow devices described herein may be usedwith as few as two processing stations to six or more processingstations with relatively minor variations in the shapes of thedirectional-flow devices.

For example, with reference now to FIG. 5, a cross-section of onestation 501 of a multi-station substrate-processing tool 500 using anRPC directional-flow device 511 in accordance with an embodiment of thedisclosed subject matter is shown. FIG. 5 is shown to include a processchamber 503, which may include, for example, four processing chambers.Each processing station includes a gas-distribution showerhead 505 and asubstrate pedestal 507 configured to hold a substrate (not shown in FIG.5) undergoing processing. Although the RPC directional-flow device 511is shown to direct the cleaning gases into areas between thegas-distribution showerhead 505 and the substrate pedestal 507, a personof ordinary skill in the art, upon reading and understanding thedisclosed subject matter, will recognize that the cleaning gases can bedirected into one more additional areas within the multi-stationsubstrate-processing tool 500 as well. For example, the RPCdirectional-flow device 511 can be positioned to deliver the cleaninggases above the gas-distribution showerhead 505, between thegas-distribution showerhead 505 and the substrate pedestal 507 (asshown) and/or below the substrate pedestal 507 at different time periodsduring a cleaning cycle.

One or more radical species may be generated from various types ofcleaning gases (e.g., fluorine-containing compounds as described above)in an RPC reactor (not shown but the reactor may the same as or similarto the RPC reactor 205 of FIG. 2A). The cleaning gases and the radicalspecies enter the process chamber 503 of the multi-stationsubstrate-processing tool 500 via a process-gas inlet 509 coupled to themulti-station substrate-processing tool 500 from the RPC reactor. Thecleaning gases and the radical species are then split into substantiallyuniform flows 513 on either side of the RPC directional-flow device 511.(A person of ordinary skill in the art will recognize that the flow ofcleaning gases is also substantially equally split in planes in front ofand behind the given cross-sectional view as will become more apparentwith regard to, for example, FIGS. 6A through 6C, described below).

FIGS. 6A through 6C show various exemplary embodiments of an RPCdirectional-flow device in accordance the disclosed subject matter. Forexample, the embodiment of an RPC directional-flow device 600 of FIG. 6Ais shown to include an incoming cleaning-gas diversion hub 601 (orgenerally, an incoming-gas diversion hub) surrounded by a substantiallyuniform ramped area 603. The skilled artisan will recognize thatincoming cleaning gases will be split substantially uniformly in alldirections after impinging on the incoming cleaning-gas diversion hub601.

FIG. 6B is an embodiment that is shown to include an RPCdirectional-flow device 630 having an incoming cleaning-gas diversionhub 631. However, in contrast to the RPC directional-flow device 600 ofFIG. 6A, the incoming cleaning-gas diversion hub 631 is surrounded by,in this example, four distinct, ramped gas-diversion areas 633 (fourramped gas-diversion areas). Each of the ramped gas-diversion areas 633is separated from others of the ramped gas-diversion areas 633 by araised wall 635. The raised walls 635 help to more fully separate anddirect incoming cleaning gases and accompanying radical species into theramped gas-diversion areas 633. Consequently, the skilled artisan willrecognize that incoming cleaning gases will be split substantiallyuniformly into directions of the four distinct, ramped gas-diversionareas 633 after impinging on the incoming cleaning-gas diversion hub631.

FIG. 6C is an embodiment that is shown to include an RPCdirectional-flow device 650 having an incoming cleaning-gas diversionhub 651. Each of a plurality of ramped gas-diversion areas 653 isseparated from others of the ramped gas-diversion areas 653 by a raisedwall 655. The raised walls 655 help to more fully separate and directincoming cleaning gases and accompanying radical species into the rampedgas-diversion areas 653. Consequently, the skilled artisan willrecognize that incoming cleaning gases will be split substantiallyuniformly into directions of the four distinct, ramped gas-diversionareas 653 after impinging on the incoming cleaning-gas diversion hub651.

In contrast to the RPC directional-flow device 630 of FIG. 6B, the RPCdirectional-flow device 650 of FIG. 6C also includes a smaller (e.g.,narrower) final exit-ramp of the ramped gas-diversion area 653. Thefinal exit-ramp may be designed or optimized to deliver or focus thecleaning gases and accompanying radicals into specific areas, forexample, between the gas-distribution showerhead 505 and the substratepedestal 507 of FIG. 5.

A person of ordinary skill in the art will recognize that either of theRPC directional-flow devices 630, 650 of FIG. 6B or 6C, respectively,may have fewer than four or more than four distinct, rampedgas-diversion areas 633, 653 and accompanying one of the raised walls635, 655.

Any of the RPC directional-flow devices 600, 630, 650 of FIG. 6A throughFIG. 6C may be formed from, various materials including, for example, anultra-high purity material such as various forms of aluminum, aluminumalloys, ceramic materials (such as, for example, aluminum oxide, Al₂O₃,and aluminum nitride, AlN), and other metallic (e.g., various grades ofstainless steel) and non-metallic materials. Depending upon a particularuse, other materials may also be used separately or in combination withthe materials noted above. For example, in one specific exemplaryembodiment, the RPC directional-flow devices 600, 630, 650 may be formedfrom a variety of high-performance alloys (also known as superalloys),known in the art. These high-performance alloys include, for example,Inconel® (available from different sources including Inco AlloysInternational, Inc., Huntington, W. Va., USA) or Hastelloy® (availablefrom different sources including Haynes Stellite Company, Kokomo, Ind.,USA and Union Carbide Corporation, New York, N.Y., USA). Such a materialmay be electropolished to, for example, a surface roughness value of Raless than about, for example, 0.5 μm or less than about 0.1 μm, or evenless depending upon a given process. In other embodiments, the RPCdirectional-flow devices 600, 630, 650 may be, for example, abrasiveblasted, bead-blasted, or otherwise finished to have a surface textureto more fully disperse the cleaning gases and accompanying radicals.Further, a person of ordinary skill in the art, upon reading andunderstanding the disclosed subject matter, will recognize that the typeof cleaning gas employed may also influence the type of material and thesurface roughness or texture from which the RPC directional-flow devices600, 630, 650 are formed. As noted above, various other materials mayalso be considered in combination with these high-performance alloys(e.g., such as aluminum, stainless steel, or other types of materialsdepending upon a particular application). Any of these materials mayfurther be plated, coated, or otherwise have another type of coating(e.g., anodization) added.

Other materials to form the RPC directional-flow devices may also beconsidered. For example, materials that are at least somewhat resistantto etching from the cleaning gases employed may be considered. Incertain applications, such materials should be able to withstandtemperatures, without significant deformation, from about 250° C. up toabout 550° C. at a temperature ramp rate of about 6° C./minute to about10° C./minute. In various applications, a ramp rate of temperature maynot be a consideration. In specific exemplary embodiments, the materialsused to form the RPC directional-flow devices may have a face-flatnesscreep of less than about 100 μm (approximately 0.004 inches) for aminimum of 5 years. In various applications, creep or overall flatnessmay not be a consideration. In these applications, changes in creep orflatness will not affect the clean-gas flow.

FIGS. 7A and 7B various exemplary embodiments of a multi-walled RPCdirectional-flow device in accordance the disclosed subject matter. Forexample, FIG. 7A shows an embodiment that includes a multi-walled RPCdirectional-flow device 700 having an incoming cleaning-gas diversionhub 701. The incoming cleaning-gas diversion hub 701 is surrounded by,in this example, four distinct, ramped gas-diversion areas 703. Each ofthe ramped gas-diversion areas 703 is separated from others of theramped gas-diversion areas 703 by a multi-ribbed wall 705. Themulti-ribbed walls 705 help to more fully separate and direct incomingcleaning gases and accompanying radical species into the rampedgas-diversion areas 703. Consequently, the skilled artisan willrecognize that incoming cleaning gases will be split substantiallyuniformly into directions of the four distinct, ramped gas-diversionareas 703 and into the four distinct areas between the multi-ribbed wall705 portions after impinging on the incoming cleaning-gas diversion hub701 (e.g., a total of eight distinct areas or channels into which gascan flow; eight ramped gas-diversion areas).

With reference now to FIG. 7B, an embodiment that includes amulti-walled RPC directional-flow device 730 having an incomingcleaning-gas diversion hub 731 is shown. The incoming cleaning-gasdiversion hub 731 is surrounded by, in this example, four distinct,ramped gas-diversion areas 733. Each of the ramped gas-diversion areas733 is separated from others of the ramped gas-diversion areas 733 by amulti-ribbed wall 735. The multi-ribbed walls 735 help to more fullyseparate and direct incoming cleaning gases and accompanying radicalspecies into the ramped gas-diversion areas 733. Consequently, theskilled artisan will recognize that incoming cleaning gases will besplit substantially uniformly into directions of the four distinct,ramped gas-diversion areas 733 and into the four distinct areas betweenthe multi-ribbed wall 735 portions after impinging on the incomingcleaning-gas diversion hub 731 (e.g., a total of eight distinct areas orchannels into which gas can flow; eight ramped gas-diversion areas).

In various embodiments, the various directional-flow devices having thefour additional channels (e.g., the four distinct areas between themulti-ribbed wall 705, 735 portions) allows the directional-flow devicesto direct cleaning of raised ribs in the process chamber that formpockets, or other areas around the pedestal as shown in, for example,FIG. 5.

In contrast to the multi-walled RPC directional-flow device 700 of FIG.7A, the multi-walled RPC directional-flow device 730 of FIG. 7B alsoincludes a smaller (e.g., narrower) exit-ramp area 737. The exit-ramparea 737 may be designed or optimized to deliver or focus the cleaninggases and accompanying radicals into specific areas, for example,between the gas-distribution showerhead 505 and the substrate pedestal507 of FIG. 5.

Each of the multi-walled RPC directional-flow device 700, 730 may beconstructed using the same or similar materials, or combinations ofmaterials, as discussed with regard to FIGS. 6A through 6C, above.Further, the multi-ribbed walls 705, 735 of FIGS. 7A and 7B can act asheat sinks and may provide more effective cooling (both thermallyconductive and thermally convective due to the increased area of themulti-ribbed walls 705, 735 as compared with the raised walls 635, 655of FIGS. 6B and 6C. This cooling function provided by the multi-ribbedwalls 705, 735 may be advantageous in certain applications. In otherapplications, the multi-ribbed walls 705, 735 may be heated (e.g., froma bottom side by techniques known in the art) to reduce or preventrecombination effects of a cleaning-gas species.

FIGS. 8A and 8B show exemplary physical dimensions for the multi-walledRPC directional-flow devices of FIGS. 7A and 7B. These physicaldimensions are provided as examples only to help a person of ordinaryskill in the art better understand the disclosed subject matter.However, upon reading and understanding the disclosed subject matter,the person of ordinary skill in the art will recognize that the physicaldimensions can change significantly based on a size of the variousprocess stations (e.g., whether the stations are designed to accommodate300 mm or 450 mm round substrates, square or rectangular flat-paneldisplays, flowrates and pressures encountered within the processingstations, physical separations between components within the processingstation, a total number of processing stations, and a number of otherfactors). Therefore, the physical dimensions provided herein areexemplary only.

For example, FIG. 8A shows a plan view 800 of a multi-walled RPCdirectional-flow device that may be the same as or similar to themulti-walled RPC directional-flow device of FIGS. 7A and 7B. FIG. 8A isshown to include an incoming cleaning-gas diversion hub 801 surroundedby, in this example, four distinct, ramped gas-diversion areas 803. Eachof the ramped gas-diversion areas 803 is separated from others of theramped gas-diversion areas 803 by a multi-ribbed wall 805. Although theincoming cleaning-gas diversion hub 801 is shown as being substantiallydome-shaped (e.g., a convex geometry) and without particular dimensions,a person of ordinary skill in the art will recognize that shapes otherthan dome shaped and implied radii of the incoming cleaning-gasdiversion hub 801 (or any of the other incoming cleaning-gas diversionhubs 601, 631, 651, 701, 731) may be used. For example, a shape anddimensions (e.g., an interior radius of the incoming cleaning-gasdiversion hub may be determined for a given application, types of gases,and physical properties of the gases (e.g., gas viscosities, flowratesof the gases, etc.). These shape and dimensions designs may bedetermined by various techniques such as through empirical techniques orthrough CFD analysis, or a combination of the two techniques. The personof ordinary skill in the art will recognize how the shape and dimensionsmay be determined based upon reading and understanding the disclosedsubject matter.

The exemplary physical dimensions include an overall first width, d₁, ofabout 241 mm (approximately 9.5 inches), a distance from a centerline ofthe multi-walled RPC directional-flow device to a side indentation, d₂,of about 112.8 mm (approximately 4.44 inches), an overall second widthd₃, of about 241 mm (approximately 9.5 inches), a distance from anothercenterline of the multi-walled RPC directional-flow device to an upperportion of the multi-ribbed wall 805, d₄, of about 35.6 mm(approximately 1.4 inches), and a distance from another centerline ofthe multi-walled RPC directional-flow device to an outermost portion ofthe ramped gas-diversion areas 803 d₅, of about 135.9 mm (approximately5.35 inches). A first angle, □₁, from a centerline of the multi-walledRPC directional-flow device (between the ribs of the multi-ribbed wall805) is about 45°. FIG. 8A also shows a cross-section A-A described withregard to FIG. 8B, below.

With reference now to FIG. 8B, an elevation view 830 of the of themulti-walled RPC directional-flow device of FIG. 8A is shown. FIG. 8Bshows the cross-section of FIG. 8A at A-A. The exemplary physicaldimensions include an overall height, d₉, of about 80.0 mm(approximately 3.15 inches), and a distance from the centerline of themulti-walled RPC directional-flow device to a top of the exit-ramp area(e.g., the exit-ramp area 737 of FIG. 7B) of about 96.5 mm(approximately 3.8 inches). An exemplary distance from a top portion ofthe exit-ramp area to a bottommost portion of the multi-walled RPCdirectional-flow device is shown to be about 9.91 mm (approximately 0.39inches) and a height from the bottommost portion of the multi-walled RPCdirectional-flow device to a top of the multi-ribbed wall 805 is about63.5 mm (approximately 2.5 inches). An exemplary angle, □₂, of theexit-ramp area is about 16.7°.

Any of the RPC directional-flow devices (e.g., those shown in FIGS. 6Athrough 6C and in FIGS. 7A and 7B) described above may be internallycooled (e.g., by water cooling or cooling by another fluid, such as, forexample, helium) to maintain an approximate desired temperature of theRPC directional-flow devices. Although not shown, cooling fins may beadded on internal surfaces of the devices to act as heat sinks that areconvectively cooled by a flowing liquid or other fluid passed thereby.In other embodiments, cooling fins may be formed on internal surfaces ofthe RPC directional-flow devices in a spiral path to enhance convectivecooling from the devices due to the flowing liquid. In still otherembodiments, similar types of internal cooling fins may be formed oninternal surface of the RPC directional-flow devices to be convectivelycooled by a gas passing thereby. Such a gas can be chosen to have a highspecific heat-capacity, such as helium (He).

In a specific exemplary embodiment, the RPC cleaning gases may beflowing at, for example, about 12 standard liters per minute (slpm) at apressure of about 3 Torr. In other embodiments, the RPC cleaning gasesmay be flowing at, for example, about 27.5 slpm at a pressure of about 3Torr. In still other embodiments, the cleaning gases may be flowing atflowrates less than about 12 slpm or above about 27.5 slpm. In variousembodiments, the cleaning gases may be injected into the process chamberthat are at pressures lower than about 3 Torr or higher than about 3Torr.

With concurrent reference to FIG. 5, FIG. 9A shows a CFD-basedsimulation 900 showing a vector field of an RPC inlet flow using an RPCdirectional-flow device in accordance the disclosed subject matter whenapplied to one station of a multi-station substrate-processing tool. Asdiscussed above with reference to FIGS. 4A and 4B, and as is known to aperson of ordinary skill in the art conversant with CFD analysis, only asingle process station is shown as results in remaining ones of theprocess stations (not shown) would be substantially identical in thissituation as results would be mirrored along two axes (e.g., on the backedge and the left edge of the process station).

A person of ordinary skill in the art will immediately recognize thatthe vectors of FIG. 9A are indicative of a substantially-uniformvelocity filed of the incoming RPC gases. For example, the vectorsindicate a relative velocity of gases within the process-gas inlet 509of the process chamber 503. After the gases and radical species enterthe process-gas inlet 509 and are directed to a space between thegas-distribution showerhead 505 and the substrate pedestal 507 (see FIG.5) toward a facilities exhaust-port 901, the vectors are relativelyuniform, especially when compared with the CFD simulations 400, 430 ofFIGS. 4A and 4B. Due to the substantial-uniformity, as indicated by thevelocity of the gases and radical species, there is also relatively highefficacy of the radical species for cleaning.

With continuing reference to FIG. 5, FIG. 9B shows a CFD-basedsimulation 930 showing flow streams of an RPC inlet flow using an RPCdirectional-flow device in accordance the disclosed subject matter whenapplied to one station of a multi-station substrate-processing tool. Aperson of ordinary skill in the art will recognize that the flowstreams, much like the vector fields of FIG. 9A, are indicative of asubstantially-uniform velocity of the incoming gases along across thespace between the gas-distribution showerhead 505 and the substratepedestal 507 (see FIG. 5) toward the facilities exhaust-port 901.

In the examples of FIGS. 9A and 9B, the CFD-based simulations 900, 930were run considering an incoming flowrate of the cleaning gas to beabout 27.5 slpm (or about 6.875 slpm per station, that is (27.5 slpm)/4)at a pressure of about 3 Torr. The space between a bottommost portion ofthe gas-distribution showerhead and an uppermost portion of thesubstrate pedestal is about 24.6 mm. A large number of other CFDsimulations were run using various other parameters as well.

Throughout this specification, plural instances may implementcomponents, operations, or structures described as a single instance.Although individual operations of one or more methods are illustratedand described as separate operations, one or more of the individualoperations may be performed concurrently, and nothing requires that theoperations necessarily be performed in the order illustrated. Structuresand functionality presented as separate components in exampleconfigurations may be implemented as a combined structure or component.Similarly, structures and functionality presented as a single component(e.g., various embodiments of the RPC directional-flow device) may beimplemented as separate components. These and other variations,modifications, additions, and improvements fall within the scope of thesubject matter described herein.

Further, as used herein, the term “or” may be construed in an inclusiveor exclusive sense. Further, other embodiments will be understood by aperson of ordinary skill in the art upon reading and understanding thedisclosure provided. Additionally, upon reading and understanding thedisclosure, the person of ordinary skill in the art will readilyunderstand that various combinations of the techniques and examplesprovided herein may all be applied in various combinations.

Although various embodiments are discussed separately, these separateembodiments are not intended to be considered as independent techniquesor designs. As indicated above, each of the various portions may beinter-related and each may be used separately or in combination withother embodiments of the RPC directional-flow devices discussed herein.For example, although various embodiments of methods, operations, andprocesses have been described, these methods, operations, and processesmay be used either separately or in various combinations.

Consequently, many modifications and variations can be made, as will beapparent to a person of ordinary skill in the art upon reading andunderstanding the disclosure provided herein. Functionally equivalentmethods and devices within the scope of the disclosure, in addition tothose enumerated herein, will be apparent to the skilled artisan fromthe foregoing descriptions. Portions and features of some embodimentsmay be included in, or substituted for, those of others. Suchmodifications and variations are intended to fall within a scope of theappended claims. Therefore, the present disclosure is to be limited onlyby the terms of the appended claims, along with the full scope ofequivalents to which such claims are entitled. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only and is not intended to belimiting.

The Abstract of the Disclosure is provided to allow the reader toascertain quickly the nature of the technical disclosure. The abstractis submitted with the understanding that it will not be used tointerpret or limit the claims. In addition, in the foregoing DetailedDescription, it may be seen that various features may be groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted aslimiting the claims. Thus, the following claims are hereby incorporatedinto the Detailed Description, with each claim standing on its own as aseparate embodiment.

THE FOLLOWING NUMBERED EXAMPLES INCLUDE EMBODIMENTS OF THE DISCLOSEDSUBJECT MATTER

Example 1: In an embodiment, the disclosed subject matter includes anapparatus to direct radical species is disclosed. The apparatuscomprises a remote-plasma clean (RPC) directional-flow device that isconfigured to be coupled between an RPC reactor and a multi-stationprocess chamber. The RPC directional-flow device includes multiple,ramped gas-diversion areas. Respective ones of the multiple, rampedgas-diversion areas are configured to direct at least the radicalspecies generated by the RPC reactor to a separate one of multipleprocessing stations within the multi-station process chamber. A numberof the ramped gas-diversion areas is at least equal to a number of themultiple processing stations. An incoming cleaning-gas diversion hub isarranged to receive at least the radical species from the RPC reactorand distribute at least the radical species substantially-uniformly toeach of the multiple, ramped gas-diversion areas.

Example 2: The apparatus of Example 1, wherein the RPC directional-flowdevice comprises four ramped gas-diversion areas.

Example 3: The apparatus of Example 1, wherein the RPC directional-flowdevice comprises eight ramped gas-diversion areas.

Example 4: The apparatus of any one of the preceding Examples, furthercomprising an exit-ramp area formed near an outer periphery of the RPCdirectional-flow device, the exit-ramp area being narrower than theramped gas-diversion area in which the exit-ramp area is formed.

Example 5: The apparatus of any one of the preceding Examples, furtherincluding a multi-ribbed wall separating each of the rampedgas-diversion areas. The apparatus also includes a channel locatedbetween each multi-ribbed wall separating the ramped gas-diversion areasto direct at least the radical species generated by the RPC reactor.

Example 6: The apparatus of any one of the preceding Examples, whereinthe incoming cleaning-gas diversion hub is substantially dome-shaped.

Example 7: The apparatus of any one of the preceding Examples, whereinthe RPC directional-flow device is positioned to direct at least theradical species above each of multiple gas-distribution showerheads inthe multi-station process chamber.

Example 8: The apparatus of any one of the preceding Examples, whereinthe RPC directional-flow device is positioned to direct at least theradical species between each of multiple gas-distribution showerheadsand respective multiple substrate pedestals in the multi-station processchamber.

Example 9: The apparatus of any one of the preceding Examples, whereinthe RPC directional-flow device is positioned to direct at least theradical species below each of multiple substrate pedestals in themulti-station process chamber.

Example 10: In an embodiment, a directional-flow device to distribute anincoming-gas flow is disclosed. The directional-flow device includesmultiple, ramped gas-diversion areas. Respective ones of the multiple,ramped gas-diversion areas are arranged to direct the incoming-gas flowto a separate one of multiple processing stations within a multi-stationprocess chamber. A number of the ramped gas-diversion areas is at leastequal to a number of the multiple processing stations. An incoming-gasdiversion hub is arranged to receive and split the incoming-gas flowsubstantially-uniformly and distribute the incoming-gas flow to at leasteach of the multiple ramped gas-diversion areas.

Example 11: The apparatus of Example 10, wherein the directional-flowdevice comprises four ramped gas-diversion areas.

Example 12: The apparatus of Example 10, wherein the RPCdirectional-flow device comprises eight ramped gas-diversion areas.

Example 13: The apparatus of any one of Example 10 through Example 12,wherein the incoming-gas diversion hub is substantially dome-shaped.

Example 14: In an embodiment, a remote-plasma clean (RPC)directional-flow device is disclosed. The RPC directional-flow deviceincludes multiple, ramped gas-diversion areas. Respective ones of themultiple, ramped gas-diversion areas are configured to direct at least aradical species generated by an RPC reactor to a separate one ofmultiple processing stations within a multi-station process chamber. Amulti-ribbed wall separates each of the ramped gas-diversion areas. Themulti-ribbed wall has a channel located between each multi-ribbed wallseparating the ramped gas-diversion areas. An incoming cleaning-gasdiversion hub is arranged to receive at least the radical species fromthe RPC reactor and distribute at least the radical speciessubstantially-uniformly to each of the multiple, ramped gas-diversionareas.

Example 15, the RPC directional-flow device of Example 14, wherein anumber of the multiple, ramped gas-diversion areas is at least equal toa number of the multiple processing stations.

Example 16, the RPC directional-flow device of either Example 14 orExample 15, wherein a number of the channels is at least equal to anumber of the multiple processing stations.

Example 17, the RPC directional-flow device of any one of Example 14through Example 16, wherein the incoming cleaning-gas diversion hub issubstantially dome-shaped.

Example 18, the RPC directional-flow device of any one of Example 14through Example 17, wherein the RPC directional-flow device ispositioned within the multi-station process chamber to direct at leastthe radical species above each of multiple gas-distribution showerheadsin the multi-station process chamber.

Example 19, the RPC directional-flow device of any one of Example 14through Example 18, wherein the RPC directional-flow device ispositioned within the multi-station process chamber to direct at leastthe radical species between each of multiple gas-distributionshowerheads and respective multiple substrate pedestals in themulti-station process chamber.

Example 20, the RPC directional-flow device of any one of Example 14through Example 18, wherein the RPC directional-flow device ispositioned within the multi-station process chamber to direct at leastthe radical species below each of multiple substrate pedestals in themulti-station process chamber.

1. (canceled)
 2. An apparatus for use in semiconductor processing, theapparatus comprising: a remote-plasma directional-flow device that isconfigured to be coupled between a remote-plasma reactor and amulti-station process chamber having a plurality of processing stations,the remote-plasma directional-flow device comprising: a plurality oframped gas-diversion areas, respective ones of the plurality of rampedgas-diversion areas configured to direct at least radical speciesgenerated by the remote-plasma reactor to a separate one of theplurality of processing stations within the multi-station processchamber, a number of the plurality of ramped gas-diversion areas beingequal to or greater than a number of the plurality of processingstations; and an incoming gas diversion hub configured to receive atleast the radical species from the remote-plasma reactor and distributeat least the radical species substantially-uniformly to each of theplurality of ramped gas-diversion areas.
 3. The apparatus of claim 2,wherein the remote-plasma directional-flow device comprises four rampedgas-diversion areas.
 4. The apparatus of claim 2, wherein theremote-plasma directional-flow device comprises eight rampedgas-diversion areas.
 5. The apparatus of claim 2, further comprising anexit-ramp area near an outer periphery of the remote-plasmadirectional-flow device, the exit-ramp area being narrower than theramped gas-diversion area in which the exit-ramp area is located.
 6. Theapparatus of claim 2, further comprising: a multi-ribbed wall separatingeach of the ramped gas-diversion areas; and a channel located betweenportions of each multi-ribbed wall, wherein the channel is configured todirect at least the radical species generated by the remote-plasmareactor.
 7. The apparatus of claim 2, wherein the incoming gas diversionhub is substantially dome-shaped.
 8. The apparatus of claim 2, whereinthe remote-plasma directional-flow device is positioned to direct atleast the radical species above each of multiple gas-distributionshowerheads in the multi-station process chamber.
 9. The apparatus ofclaim 2, wherein the remote-plasma directional-flow device is positionedto direct at least the radical species between each of multiplegas-distribution showerheads and respective multiple substrate pedestalsin the multi-station process chamber.
 10. The apparatus of claim 2,wherein the remote-plasma directional-flow device is positioned todirect at least the radical species below each of multiple substratepedestals in the multi-station process chamber.
 11. A directional-flowdevice to distribute an incoming-gas flow, the directional-flow devicecomprising: a gas diversion hub having a top surface with a convexgeometry; a plurality of ramped gas-diversion areas intersecting the topsurface of the gas diversion hub and arranged around the gas diversionhub, wherein each of the plurality of ramped gas-diversion areascomprises a first section connected to the top surface of the gasdiversion hub and a second section connected to the first section,wherein the first section has a concave geometry.
 12. Thedirectional-flow device of claim 11, wherein the directional-flow devicecomprises four ramped gas-diversion areas.
 13. The directional-flowdevice of claim 11, wherein the second section is sloped linearlydownwards from the first section.
 14. The directional-flow device ofclaim 11, further comprising: a plurality of raised walls that separatethe plurality of ramped gas-diversion areas from each other.
 15. Aremote-plasma clean (RPC) directional-flow device, comprising: aplurality of ramped gas-diversion areas, respective ones of theplurality of ramped gas-diversion areas being configured to direct atleast radical species generated by an RPC reactor to a separate one of aplurality of processing stations within a multi-station process chamber;a multi-ribbed wall separating each of the ramped gas-diversion areas;and an incoming cleaning-gas diversion hub configured to receive atleast the radical species from the RPC reactor and distribute at leastthe radical species substantially-uniformly to each of the plurality oframped gas-diversion areas.
 16. The RPC directional-flow device of claim15, wherein a number of the plurality of ramped gas-diversion areas isequal to or greater than a number of the plurality of processingstations.
 17. The RPC directional-flow device of claim 15, furthercomprising: a plurality of channels, each of the plurality of channelslocated between portions of the multi-ribbed wall, wherein the pluralityof channels are configured to direct at least the radical speciesgenerated by the RPC reactor, wherein a number of the channels is equalto or greater than a number of the plurality of processing stations. 18.The RPC directional-flow device of claim 15, wherein the incomingcleaning-gas diversion hub is substantially dome-shaped.
 19. The RPCdirectional-flow device of claim 15, wherein the RPC directional-flowdevice is positioned within the multi-station process chamber to directat least the radical species above each of multiple gas-distributionshowerheads in the multi-station process chamber.
 20. The RPCdirectional-flow device of claim 15, wherein the RPC directional-flowdevice is positioned within the multi-station process chamber to directat least the radical species between each of multiple gas-distributionshowerheads and respective multiple substrate pedestals in themulti-station process chamber.
 21. The RPC directional-flow device ofclaim 15, wherein the RPC directional-flow device is positioned withinthe multi-station process chamber to direct at least the radical speciesbelow each of multiple substrate pedestals in the multi-station processchamber.
 22. An apparatus for use in semiconductor processing, theapparatus comprising: a gas directional-flow device comprising: a gasdiversion hub having a curved top surface; and a plurality of ramped gasdiversion areas intersecting the curved top surface and symmetricallyarranged about the gas diversion hub, wherein each of the plurality oframped gas diversion areas comprises a first section connected to thecurved top surface and a second section connected to the first section,wherein the first section is sloped downwards in a first profile fromthe curved top surface towards an outer periphery of the gasdirectional-flow device, wherein the second section is sloped downwardsin a second profile different than the first profile, wherein the firstprofile is a non-linear profile.
 23. The apparatus of claim 22, whereinthe second profile is a linear profile.
 24. The apparatus of claim 22,wherein the curved top surface is substantially dome-shaped.
 25. Theapparatus of claim 22, wherein the curved top surface has a convexgeometry and the first profile of the first section has a concavegeometry.
 26. The apparatus of claim 22, wherein an initial slope of thefirst profile adjacent to the curved top surface of gas diversion hub issteeper than a terminal slope of the first profile adjacent to thesecond section of the ramped gas diversion areas.
 27. The apparatus ofclaim 26, wherein the second section of the ramped gas diversion areadefines an exit-ramp area having an exit-ramp slope, wherein theexit-ramp slope is steeper than the terminal slope of the first profile.28. The apparatus of claim 27, wherein the exit-ramp slope has an angleof approximately 16.7°.
 29. The apparatus of claim 22, wherein the firstsection expands in width from the curved top surface to the secondsection.
 30. The apparatus of claim 22, wherein the second section ofthe ramped gas diversion area defines an exit-ramp area, the exit-ramparea being narrower in width than a terminal end of the first section.31. The apparatus of claim 22, wherein the first section is longer thanthe second section.
 32. The apparatus of claim 22, wherein thegas-directional flow device further comprises: a plurality of raisedwalls that separate the plurality of ramped gas diversion areas fromeach other.
 33. The apparatus of claim 32, wherein the gasdirectional-flow device further comprises: a plurality of channelsdefined in areas between each of the plurality of raised walls.
 34. Theapparatus of claim 22, further comprising: a multi-station processchamber comprising a plurality of processing stations; and aremote-plasma reactor configured to generate radical species, whereinthe gas directional-flow device is positioned between the remote-plasmareactor and the multi-station process chamber, wherein the gasdirectional-flow device is configured to distribute at least radicalspecies substantially-uniformly to each of the plurality of ramped gasdiversion areas.
 35. The apparatus of claim 34, wherein a number of theplurality of ramped gas diversion areas is equal to or greater than anumber of the plurality of processing stations.